The present invention relates to the processing of oil-containing solids such as tar sands to recover hydrocarbons therefrom. More particularly, it relates to a process wherein the oil sands are comminuted and then admixed with a liquid hydrocarbon solvent which is capable of dissolving the tar component of the sands, hereinafter called bitumen. Thereafter the solvent-containing system is processed to remove the coarser sand particles and then to recover a bitumen product stream along with one or more solvent streams which are recycled through the system to effect good recovery of the bitumen from the separated sand components. A process of this character is self-contained and thus differs from those wherein separation of the bitumen is effected by the use of hot water. Thus, in the present method the solvent employed can be obtained from the bitumen at the plant site as the bitumen is distilled or is subjected to processing operations such as cracking, vis breaking, coking or the like which give rise to solvent fractions. The "solvent" so obtained is usually highly aromatic and may comprise a mixture of various liquid hydrocarbon compounds such as benzene and toluene, for example. In contrast, when working with a hot water extraction system, water must be obtained at the plant site in large volumes, which frequently is difficult and expensive. Disposal of the oil- and salt-contaminated water streams recovered from the process is even more difficult. Typical of the tar sands which can be employed in a practice of this invention are the Athabasca tar sands of Canada, the Edna tar sands of California or the Green River tar sands of Utah. Sands of this character typically have an oil (bitumen) content of 8 to 15%, with solids and H.sub.2 O making up the remainder. Typically the coarser sand particles which are removed by the present invention constitute from about 75 to 85% of the tar sand, while the fine sand and clay particles which are present constitute only about 2 to 5%. Thus, when a process such as this is employed which essentially removes the coarser sand particles at an extremely low cost, the remainder (fines) can be removed by centrifuging or other conventional means at a low cost made possible by the small amount of the said materials which remain in the bitumen-containing stream to be worked up.
Also contributing to the economy of the present invention is the fact that the coarse sand particles removed, which carry with them appreciable amounts of bitumen, can be efficiently washed and transported with the solvent material employed in the system. Thus, washing and sand-transporting steps become much more difficult and expensive when coarse sand material is admixed with fines, as represented by fine sand particles, clay and the like.